JP2011191110A - Stick-slip detecting device and detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine the state of a stick slip corresponding to the state of control, in a more accurate way. <P>SOLUTION: For example, a control valve is controlled from the outside via a positioner, or is controlled autonomously by an adjusting mechanism in the valve. As a result of control, displacement of a valve shaft (movable part) is changed. Additionally, a process variable, such as a flow rate of fluid passing through the control valve, is changed corresponding to the amount of displacement of the valve shaft. In this way, on the basis of the amount of displacement of the valve shaft and that of measurement results (measurement values) of the process variable, a diagnosis operation control unit 107 controls the operation of a diagnosis unit 100. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stick-slip detection device and a detection method for detecting stick-slip in the operation of a device having a sliding surface having a contact friction portion such as a control valve or a gas governor.

  The failure of the control valve or gas governor can be diagnosed by detecting the occurrence of stick-slip in the sliding portion. For example, as shown in FIG. 10, the stick slip is generated depending on the state of the contact sliding portion 1003 between the piston 1001 and the cylinder 1002. For example, this stick-slip occurs when foreign matter enters the contact sliding portion 1003. Therefore, stick slip can be detected by measuring the displacement of the piston 1001 and monitoring the measured displacement state (see Patent Document 1).

  Here, the stick-slip detection described in Patent Document 1 will be briefly described. In this detection technique, the displacement of the piston 1001 is detected, the first state quantity is calculated from the detected displacement, the second state quantity is calculated from the detected displacement, and the first state quantity obtained from the displacement during normal operation is obtained. The stick slip is detected (determined) by comparing the relationship between the first state quantity and the second state quantity with the relation between the calculated first state quantity and the calculated second state quantity. Yes.

  For example, the average of the absolute values of the first-order difference values of displacement is used as the first state quantity, and the square root of the mean square of the first-order difference values of displacement is used as the second state quantity. When the displacement of the piston 1001 is discretely detected and the i-th detected displacement is Xi, each state quantity is expressed by the following expressions (1) and (2) (where N is the state quantity) This is the number of displacement data used to calculate.

The frequency distribution of the absolute value (| X _{i + 1} −X _i |) of the first-order difference value of the displacement is as shown in FIGS. 11A and 11B. FIG. 11A shows a normal state, and the occurrence frequency gradually decreases as the difference value increases. On the other hand, when stick-slip has occurred, it is in a fixed state for most of the time, and sometimes a slip state is generated. For this reason, as shown in FIG. 11B, the frequency of the first-order difference value takes a value close to 0 with high frequency (corresponding to the fixed state), but may take a relatively large value with low frequency (slip). Corresponding to the state). In such a state where stick slip occurs, the ratio of the first state quantity (average absolute value of the first-order difference value) and the second state quantity (square root of the mean square of the first-order difference value) is normal. Since it becomes larger than the time, stick-slip can be detected by monitoring the ratio of the two state quantities.

Japanese Patent No. 3254624

  However, the above-described technique has a problem that the stick-slip state may be erroneously determined depending on the control state of the movable part (piston).

  In the technique described above, it is detected from the relationship between the two state quantities calculated from the displacement of the movable part and the relationship between the movement of the stick-slip detection object in the fixed state and the sliding state. This is determined using only the displacement of the movable part. For this reason, if the movement (displacement) of the movable part is the same as in the stick-slip state, it is determined that the stick-slip has occurred even if the stick-slip has not actually occurred. However, this is a false detection.

  For example, in the control of the valve shaft position by the positioner, when the control command value (set value, set point) of the valve shaft displacement is greatly changed, the behavior of the displacement of the valve (movable part) when the control command value is changed May be similar to the stick-slip state.

  As shown in FIG. 12 (a), when two values are alternately taken and a control command value for a displacement in which the time-series signal is a rectangular wave is given, the valve shaft of the control valve corresponds to this. The displacement response is measured as a displacement measurement value of a time-series signal as shown in FIG. Such a first-order difference value of the displacement measurement value is as shown in FIG. In this case, as shown in FIG. 12C, the first-order difference value takes a value close to 0 for most of the time, but takes a large value only immediately after the control command value changes.

  This behavior is similar to the behavior of the stick-slip phenomenon, which is in a fixed state for most of the time and sometimes moves quickly and moves quickly. As a result, in the above-described technique, when the control as shown in FIG. Such false detection is likely to occur when the valve operating speed is high, and is particularly problematic for small valves.

  The present invention has been made to solve the above problems, and an object of the present invention is to make it possible to more accurately determine the state of stick-slip in accordance with the state of control.

  The stick-slip detection device according to the present invention includes a displacement detection means for detecting a displacement of a movable portion having a contact sliding portion, a first calculation means for calculating a first state quantity from the displacement, and a second from the displacement. A second calculating means for calculating a state quantity; a characteristic storage section storing a relationship between a first state quantity and a second state quantity obtained from a displacement during normal operation of the movable part that has been obtained in advance; State quantity estimating means for estimating the second state quantity from the first state quantity calculated by the first computing means using the relationship stored in the storage unit and calculating the estimated state quantity; A diagnostic unit that determines abnormality of the movable part, and a diagnostic calculation unit that determines abnormality of the movable part by comparing the second state quantity calculated by the calculation means and the estimated state quantity; Change in measured value of any process variable that changes due to displacement of moving part The and a diagnosing operation controlling unit that controls the operation of the diagnostic unit based on.

  The stick-slip detection device according to the present invention includes a displacement detection means for detecting a displacement of a movable part having a contact sliding part, a first calculation means for calculating a first state quantity from the displacement, and a first calculation from the displacement. A second calculation means for calculating the state quantity of 2, and a characteristic storage section storing a relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part obtained in advance during normal operation; By comparing the relationship between the first state quantity calculated by the first calculation means and the second state quantity calculated by the second calculation means with the relation stored in the characteristic storage unit, Based on the amount of change in the measured value of either the diagnostic part for judging the abnormality of the movable part having a diagnostic calculation means for judging the abnormality of the part, or the process variable that changes due to the displacement of the movable part and the displacement of the movable part And a diagnostic operation control unit for controlling the operation of the diagnostic unit.

  In the stick-slip detection device, the diagnostic operation control unit is preset with a change amount calculating unit that calculates a change amount of the displacement of the movable part detected by the displacement detecting unit, and a change amount calculated by the change amount calculating unit. And an operation control means for controlling the operation of the diagnosis unit by detecting that the threshold value is exceeded. In addition, the diagnostic operation control unit detects a change amount calculating unit that calculates a change amount of the measured value of the process variable, and detects that the change amount calculated by the change amount calculating unit exceeds a preset threshold value. Then, an operation control means for stopping the operation of the diagnosis unit may be provided.

  In the stick-slip detection device, the diagnosis operation control unit may control the operation of the diagnosis unit by stopping the operations of the first calculation unit and the second calculation unit. Further, the diagnostic operation control unit may control the operation of the diagnostic unit by stopping the operation of the diagnostic calculation means. Further, the diagnostic operation control unit starts the operation control of the diagnostic unit based on the determination of abnormality by the diagnostic calculation means, and the measured value of either the displacement amount of the movable portion or the process variable that changes due to the displacement of the movable portion The correctness / incorrectness of the determination of abnormality by the diagnostic calculation means may be determined based on the amount of change.

  The stick-slip detection device according to the present invention includes a displacement detection means for detecting a displacement of a movable part having a contact sliding part, a first calculation means for calculating a first state quantity from the displacement, and a first calculation from the displacement. A second calculation means for calculating the state quantity of 2, and a characteristic storage section storing a relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part obtained in advance during normal operation; A state quantity estimating means for calculating an estimated state quantity by estimating a second state quantity from the first state quantity calculated by the first computing means using a relationship stored in the characteristic storage unit; A diagnostic unit for determining an abnormality of the movable part, comprising a diagnostic calculation unit for determining an abnormality of the movable part by comparing the second state quantity calculated by the two calculation means and the estimated state quantity, and a displacement of the movable part Measured value of any process variable that varies with the amount and displacement of the moving part The amount of change and a diagnostic result discrimination unit for discriminating the correctness of abnormality determination by the diagnostic calculating means based.

  Further, the stick-slip detection method according to the present invention detects the displacement of the movable part having the contact sliding part, calculates the first state quantity from the displacement, calculates the second state quantity from the displacement, and obtains in advance. Estimating the second state quantity from the calculated first state quantity by using the relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part during normal operation A quantity is calculated, the abnormality of the movable part is judged by comparing the calculated second state quantity and the estimated state quantity, and either the displacement amount of the movable part or the process variable that changes due to the displacement of the movable part is measured. The abnormality judgment operation is controlled based on the change amount of the value.

  Further, the stick-slip detection method according to the present invention detects the displacement of the movable part having the contact sliding part, calculates the first state quantity from the displacement, calculates the second state quantity from the displacement, and obtains in advance. The relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part during normal operation is compared with the calculated relationship between the first state quantity and the second state quantity. Thus, the abnormality of the movable part is determined, and the abnormality determination operation is controlled based on the amount of change in the measured value of either the amount of displacement of the movable part or the process variable that changes due to the displacement of the movable part.

  In the stick-slip detection method, the change amount of the displacement of the movable part may be calculated, and the abnormality determining operation may be stopped when the calculated change amount exceeds a preset threshold value. Alternatively, the amount of change in the measurement value of the process variable may be calculated, and the abnormality determination operation may be stopped when the calculated amount of change exceeds a preset threshold value. In addition, even if the abnormality determination operation is stopped by determining whether the abnormality is correct based on the amount of change in the measured value of either the displacement of the movable part or the process variable that changes due to the displacement of the movable part Good.

  Further, the stick-slip detection method according to the present invention detects the displacement of the movable part having the contact sliding part, calculates the first state quantity from the displacement, calculates the second state quantity from the displacement, and obtains in advance. Estimating the second state quantity from the calculated first state quantity by using the relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part during normal operation A quantity is calculated, the abnormality of the movable part is judged by comparing the calculated second state quantity and the estimated state quantity, and either the displacement amount of the movable part or the process variable that changes due to the displacement of the movable part is measured. The correctness / incorrectness of the determination of abnormality is determined based on the amount of change in value.

  As described above, according to the present invention, the abnormality determination operation is controlled based on the amount of change in the measured value of either the displacement amount of the movable portion or the process variable that changes due to the displacement of the movable portion. Therefore, it is possible to obtain an excellent effect that the stick-slip state can be more accurately determined in accordance with the control state.

FIG. 1 is a configuration diagram showing a configuration of a stick-slip detection device according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram showing the configuration of the stick-slip detection device according to the second embodiment of the present invention. FIG. 3 is a configuration diagram showing the configuration of the stick-slip detection device according to the third embodiment of the present invention. FIG. 4 is a configuration diagram showing the configuration of the stick-slip detection device according to the fourth embodiment of the present invention. FIG. 5 is a configuration diagram showing the configuration of the stick-slip detection device according to the fifth embodiment of the present invention. FIG. 6 is a configuration diagram showing the configuration of the stick-slip detection device according to the sixth embodiment of the present invention. FIG. 7 is a configuration diagram showing the configuration of the stick-slip detection device according to the seventh embodiment of the present invention. FIG. 8 is a configuration diagram showing the configuration of the stick-slip detection device according to the eighth embodiment of the present invention. FIG. 9 is a configuration diagram showing the configuration of the stick-slip detection device according to the ninth embodiment of the present invention. FIG. 10 is a configuration diagram illustrating a configuration of an apparatus having a sliding portion. FIG. 11A is a histogram showing the frequency distribution of first-order difference values of displacement signals obtained from reciprocally sliding parts. FIG. 11B is a histogram showing the frequency distribution of the first-order difference values of displacement signals obtained from reciprocating sliding parts. FIG. 12 is a timing chart showing changes in the control command value, the displacement measurement value, and the first-order difference value of the displacement measurement value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
First, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram showing a configuration of a stick-slip detection device according to an embodiment of the present invention. The stick-slip detection device includes a diagnostic unit 100 that determines abnormality of a movable unit having a contact sliding unit such as a control valve. In addition, the stick-slip detection device stops the operation of the diagnostic unit 100 based on the amount of change in the measured value of either the amount of displacement of the movable part such as the valve body or the process variable that changes due to the displacement of the movable part. A diagnostic operation control unit 107 is provided.

  The diagnosis unit 100 includes a displacement detection unit 101, a first state quantity calculation unit (first calculation unit) 102, a second state quantity calculation unit (second calculation unit) 103, a characteristic storage unit 104, and a second state. A quantity estimation unit 105 and a diagnostic calculation unit 106 are provided.

  The displacement detection unit 101 detects (measures) the displacement of a movable part such as a valve body. The first state quantity calculator 102 calculates the first state quantity from the detected displacement of the movable part. The second state quantity calculation unit 103 calculates a second state quantity from the detected displacement of the movable part. The characteristic storage unit 104 stores the relationship between the first state quantity and the second state quantity obtained in advance from the displacement of the movable part during normal operation. The second state quantity estimation unit 105 uses the relationship stored in the characteristic storage unit 104 to estimate the second state quantity from the first state quantity calculated by the first state quantity calculation unit 102 and estimate the state Calculate the amount. The diagnosis calculation unit 106 determines the abnormality of the movable part by comparing the second state quantity calculated by the second state quantity calculation unit 103 with the estimated state quantity.

  Next, the diagnostic operation control unit 107 will be described in more detail. For example, the control valve is automatically controlled from the outside via a positioner, and is controlled by manual operation. In some cases, control is performed by an adjustment mechanism of the valve itself, such as an automatic valve. As a result of these controls, the valve shaft is displaced (changed). In addition, process variables such as the flow rate of fluid passing through the control valve change corresponding to the amount of displacement of the valve shaft. The diagnosis operation control unit 107 controls the operation of the diagnosis unit 100 based on such a change amount of a measurement result (measurement value) such as a process variable such as a valve shaft displacement amount and a flow rate.

  For example, the diagnostic operation control unit 107 compares the measured change width of the valve shaft displacement with a preset reference value, and the measured valve shaft displacement change width per unit time exceeds the reference value. If this happens, the abnormality determination operation in the diagnosis unit 100 is stopped.

  When control is performed so that the displacement of the valve shaft is greatly changed in a short time, it may be determined in the same manner as when stick-slip has occurred even in normal operation. On the other hand, the diagnosis operation control unit 107 stops the operation of the diagnosis unit 100 when the unit time change width of the measured value of the valve shaft displacement that reflects the change in the control command value exceeds the reference value. Slip detection errors can be suppressed.

  In addition, since the displacement of the valve shaft, which is a movable part, is also reflected in changes in process variables such as flow rate, erroneous detection can be controlled in the same way as described above even in measured values of process variables such as flow rate. The process variable used here is preferably a physical quantity that is directly controlled by the displacement of the movable part. For example, in the case of a control valve, it is a flow rate of fluid passing through the valve or a physical quantity (for example, pressure or temperature) controlled by operating the flow rate. Further, even if the physical quantity is not directly controlled, it can be implemented if it is a physical quantity that is linked to the displacement of the movable part and has a strong correlation. On the other hand, measurement values that do not change even when the displacement of the movable part is changed, and measurement values that are weakly correlated with the displacement of the movable part cannot be used.

  Here, the reference value will be briefly described.

  First, the case of a diagnosis target that can explicitly give a control command value from the outside will be described. A rectangular wave-shaped control command value that reciprocates between two values A1 and A2 is given to a normal movable part (detection target) that is not in a stick-slip state. It is desirable that the time interval for switching the control command value is approximately the same as the most frequent command value change interval that can occur during actual operation. Two state quantities are calculated from the displacement measurement value measured as a result of operating the movable part with this control command value, and applied to the method described in Patent Document 1 to determine whether it is normal or abnormal. If it is determined that there is an abnormality in this determination, the amount of change in the displacement of the movable part due to the given control command value is a value that can cause a false detection, so the experiment is performed again with a smaller difference between A1 and A2. .

  In this way, by operating with the control command value given on a trial basis, it is possible to determine to what extent the width between A1 and A2 (control command value change amount) is to be detected as erroneous. . Also, if the control command value is moved by this amount of change, the amount of change in the displacement of the movable part is obtained from the specifications of the device, or if measured by experiment, how much the change in the displacement of the movable part can be increased. For example, it is possible to determine whether an abnormality is erroneously detected. Therefore, the lower limit of the change amount of the displacement amount of the movable part that is determined to be abnormal is obtained by the test operation described above, and this lower limit value may be used as the reference value. When the amount of change in displacement of the movable part exceeding the reference value determined in this way is detected, it is considered that the diagnosis unit 100 erroneously detects that stick-slip has occurred, as described above. In other words, if a change in displacement exceeding the reference value is detected, false detection can be suppressed if the diagnostic operation control unit 107 stops the operation of the diagnostic unit 100. The operation of the diagnosis unit 100 may be stopped for a set time while the displacement change amount exceeds the reference value or after the displacement change amount exceeds the reference value.

  In addition, if the amount of change in the displacement of the movable part is defined as the amount of change in the lower limit value, the amount of change in the measured value of the process variable is obtained. When the amount is detected, as described above, if the diagnosis operation control unit 107 stops the operation of the diagnosis unit 100, erroneous detection can be suppressed.

  On the other hand, in the case of a device that operates without being given a control command value from the outside, such as a self-powered valve, it is possible to determine the reference value via the control command value as described above. I can't do it. In such a case, the reference value can be determined by storing the amount of change in displacement when the device to be diagnosed seems to be operating normally, such as immediately after installation. For example, two state quantities and the maximum displacement change amount in the section in which these state quantities are calculated are calculated. At this time, if it is determined by the diagnosis unit that stick-slip has occurred, the calculated displacement change amount is a value that can cause erroneous detection. The smallest displacement change amount among the maximum values of the change amount of displacement measured when the occurrence of stick-slip that can be determined to be erroneous detection is determined can be used as the reference value.

  If there is a mathematical model to be detected normally, the reference value can be similarly determined using computer simulation instead of the above-described method for determining the reference value. However, in this case, it is necessary to calculate the state quantity after adding a disturbance equivalent to the error of the displacement detection unit 101.

  However, in determining the reference value, it is important not to stop the diagnostic unit by mistake when a stick slip actually occurs. When stick-slip occurs and the movable part is in a sliding state, the measured displacement change value is larger than that in the normal state. Since this value is usually smaller than the value of the amount of change that can cause false detection, it is unlikely to be a problem. In the case of a control valve (valve), for example, the amount of change in the displacement of the moving part due to stick-slip (difference between the displacement before and after the slip) is the maximum displacement of the control valve (the displacement when the valve is fully opened and fully closed). Difference) is about 0.5% to 2%, and at most about 5%. On the other hand, the amount of change when erroneous detection is occurring is about 20% to 100% of the maximum displacement, and is about 10% even if it is relatively small.

  Under such circumstances, when the above-described reference value is excessively small, there is a possibility that the diagnosis unit may be stopped until stick slip actually occurs. Therefore, when determining the reference value for the amount of change, it is preferable to confirm that the reference value is not a small value that can be taken even when stick-slip occurs.

  In addition, if the above-mentioned reference value is less than or equal to the magnitude of noise or disturbance when measuring moving part displacement or process variables, there is a risk of erroneously stopping the diagnostic operation due to the influence of noise or disturbance. is there. Therefore, when determining the reference value for the amount of change, it is preferable to confirm that it is sufficiently larger than the amount of change that can normally occur due to measurement noise, disturbance, or the like.

  The diagnosis operation control unit 107 may stop the determination operation in the diagnosis unit 100 by stopping the calculation operation in the first state quantity calculation unit 102 and the second state quantity calculation unit 103, for example. Further, for example, the determination operation in the diagnosis unit 100 may be stopped by stopping the operation of the diagnosis calculation unit 106. Further, the diagnostic operation control unit 107 stops the operation of the diagnostic unit 100 as described above, and after the set time has elapsed, or per unit time of the displacement of the valve shaft (movable unit) or the process variable. After the change width becomes smaller than a predetermined value, the operation of the diagnosis unit 100 is restarted (started).

  Here, there are various time delays before comparing the reference value with the displacement of the valve shaft and the variation of the process variable. The cause of the delay is the delay due to the calculation time of the change amount, the delay until the change of the moving part affects the process variable (for example, the transport delay required for the fluid to flow from the control valve to the flow meter), the process variable There is a delay due to the measuring equipment. For this reason, when it is detected that the amount of change exceeds the reference value, the state is already unsuitable for diagnosis, and the diagnosis unit 100 may have already made a false detection. In such a case, for example, the operation of the diagnosis unit 100 may be delayed such that the diagnosis result by the diagnosis unit 100 is output with a delay corresponding to the time delay described above. For example, the first state quantity calculation unit 102 and the second state quantity calculation unit 103 may perform the calculation of the state quantity with a delay. In addition, the displacement detection unit 101 may include a temporary storage unit that temporarily stores the detection result, and may output the detection result with a delay corresponding to the time delay described above.

  In addition, when the diagnostic operation unit 106 determines that the movable unit is abnormal, the diagnostic operation control unit 107 detects that the amount of change in the measured value that has already been measured exceeds the reference value. The output of the abnormality determination from 100 may be stopped. In particular, when it takes time until the abnormality calculation by the diagnosis calculation unit 106, the measured value of the process variable measured when the diagnosis calculation unit 106 determines that there is an abnormality in the movable unit includes the value of the movable unit at the time of abnormality determination. The control status may be reflected. In such a case, when the diagnostic calculation unit 106 determines that there is an abnormality in the movable unit, the diagnostic operation control unit 107 indicates that the amount of change in the measured value of the process variable being measured exceeds the reference value. If detected, the output of the abnormality determination from the diagnosis unit 100 may be stopped.

  As described above, in the present embodiment, first, the displacement of the movable portion having the contact sliding portion is detected, then the first state quantity is calculated from the displacement, and then the second state is calculated from the calculated displacement. Next, the first state quantity calculated by using the relationship between the first state quantity and the second state quantity obtained from the displacement during normal operation of the movable part obtained in advance is calculated. Then, the second state quantity is estimated to calculate the estimated state quantity, and then the abnormality of the movable part is determined by comparing the calculated second state quantity with the estimated state quantity. The feature is that the determination operation of abnormality is stopped based on the amount of change in the measured value of either the amount of displacement or the process variable.

  According to this embodiment, the diagnostic operation control unit 107 controls the operation of the diagnostic unit 100 based on the amount of change in the measured value of either the displacement amount of the movable portion or the process variable. It is possible to more accurately determine the state of stick-slip according to the state of control, such as suppressing erroneous detection of stick-slip.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a configuration diagram showing the configuration of the stick-slip detection device according to the second embodiment of the present invention. This stick-slip detection device stops the operation of the diagnostic unit 200 based on the amount of change in the measured value of the displacement amount of the movable unit and the diagnostic unit 200 that determines the abnormality of the movable unit having the contact sliding unit. A diagnostic operation control unit 207 is provided.

  The diagnosis unit 200 includes a displacement detection unit 201, a first state quantity calculation unit 202 (first calculation unit), a second state quantity calculation unit 203 (second calculation unit), a characteristic storage unit 204, and a second state quantity estimation. Unit 205 and diagnostic operation unit 206. The diagnostic operation control unit 207 includes a change amount calculation unit 271 and an operation control unit 272.

  The displacement detector 201 detects (measures) the displacement of a movable part such as a valve body and outputs a digital displacement signal. The displacement detection unit 201 outputs the detected displacement signal to the first state quantity calculation unit 202 and the second state quantity calculation unit 203 after the set delay time. On the other hand, the displacement detection unit 201 immediately outputs the detected displacement signal to the change amount calculation unit 271.

  The first state quantity calculation unit 202 calculates the root mean square of the first-order difference value as the first state quantity from the displacement signal output from the displacement detection unit 201 as the measured value indicating the detected displacement of the movable part. Further, the second state quantity calculation unit 203 calculates the mean square of the second-order difference values as the second state quantity from the displacement signal output from the displacement detection unit 201. The mean square of the first-order difference value and the mean square of the second-order difference value may be calculated using the following formulas (3) and (4).

However, (delta) x is the difference of x between (DELTA) t, and calculates | requires by the following formula | equation (5). Further, δ ² x is a difference of δx between Δt, and is similarly obtained.

  The characteristic storage unit 204 stores a relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part that is obtained in advance during normal operation. For example, in the characteristic storage unit 204, as a relationship (characteristic expression) between the mean square of the first-order difference value and the mean square of the second-order difference value of the displacement signal in a state where the sliding of the movable part is normal, for example, A characteristic equation that is linearly approximated by two constants A and B as shown in equation (6) is stored.

  The second state quantity estimation unit 205 uses the relationship stored in the characteristic storage unit 204 to calculate the second state quantity from the first state quantity calculated by the first state quantity calculation unit 202 (the mean square of the first-order difference values). Is estimated to calculate the estimated state quantity. For example, the second state quantity estimation unit 205 calculates the estimated state quantity corresponding to the second-order difference value by substituting the root mean square value of the first-order difference value calculated by the first state quantity calculation unit 202 into Equation (6). .

  The diagnosis calculation unit 206 determines the abnormality of the movable part by comparing the second state quantity calculated by the second state quantity calculation unit 203 with the estimated state quantity. For example, the diagnosis calculation unit 206 obtains a difference between the mean square of the second-order difference value calculated by the second state quantity calculation unit 203 and the estimated state quantity estimated by the second state quantity estimation unit 205, for example, When the difference is larger than a predetermined value, it is determined that stick-slip has occurred.

  As described above, while the diagnosis unit 200 determines stick-slip (abnormality of the movable unit), in the present embodiment, the diagnostic operation control unit 207 detects (measures) the movable unit detected by the displacement detection unit 201. The determination operation of the diagnosis unit 200 is stopped by stopping the operations of the first state amount calculation unit 202 and the second state amount calculation unit 203 based on the change amount of the displacement amount.

  In the diagnostic operation control unit 207, first, the change amount calculation unit 271 calculates a change amount from the displacement amount (displacement signal) of the movable part detected by the displacement detection unit 201. Next, the operation control unit 272 compares the set reference value with the calculated change amount, and if the change width of the calculated change amount in unit time exceeds the reference value, the first state amount calculation is performed. The calculation operation in the unit 202 and the second state quantity calculation unit 203 is stopped. For example, when the operation control unit 272 outputs a stop signal, the operations of the first state quantity calculation unit 202 and the second state quantity calculation unit 203 are stopped.

  Here, as described above, the displacement detection unit 201 outputs a displacement signal to the first state quantity calculation unit 202 and the second state quantity calculation unit 203 after the set delay time. Therefore, after the operation control unit 272 outputs the comparison result between the reference value and the calculated change amount, the first control unit 202 and the second state calculation unit 203 can output a displacement signal. it can. As a result, the diagnosis operation control unit 207 can stop the operation before the diagnosis unit 200 (diagnosis calculation unit 206) performs the determination operation.

  As described above, in the diagnosis unit 200, the determination of stick-slip is stopped, and erroneous detection of stick-slip caused by the control state of the movable unit can be suppressed.

  By the way, in the above description, the displacement signal output from the displacement detection unit 201 is a digital signal, the mean square of the first-order difference value is calculated as the first state quantity, and the square of the second-order difference value is used as the second state quantity. Although the average was calculated, it is not limited to this. For example, as in Equation (1), the absolute value average of the first-order difference value may be calculated as the first state quantity, and the square root of the root mean square of the first-order difference value may be calculated as the second state quantity. When the displacement signal is an analog signal, the mean square of the first order differential value may be calculated as the first state quantity, and the mean square of the second order differential value may be calculated as the second state quantity.

  For example, first, the first state quantity calculation unit 202 calculates the following equation from the first-order differential value of the displacement signal when measuring the relative displacement x of two sliding objects (for example, a piston and a cylinder). As shown in (7), the root mean square during time T is obtained. In addition, the second state quantity calculation unit 203 obtains a mean square during the time T as shown in the following equation (8) from the second-order differential value of the displacement signal.

  On the other hand, the characteristic storage unit 204 has, for example, the simplest relationship (characteristic expression) as a relationship (characteristic expression) between the mean square of the first-order differential value and the mean square of the second-order differential value of the displacement signal in a normal sliding state. As shown in the following equation (9), a characteristic equation that is linearly approximated by two constants A and B is stored.

  In the second state quantity estimating unit 205, the square mean of the second order differential value is estimated from the mean square of the first order differential value obtained from the measured value using the characteristic formula shown in Expression (9). Further, in the diagnostic calculation unit 206, the mean square (estimated state quantity) of the second order differential value estimated (calculated) by the second state quantity estimating unit 205 and the square of the second order differential value calculated by the second state quantity calculating unit 203. Find the difference from the average. When this difference is larger than a predetermined value, the diagnosis calculation unit 206 determines that stick slip has occurred. Even if the root mean square of the first order differential value is estimated from the mean square of the second order differential value, and the mean square of the estimated first order differential value is compared with the root mean square of the actual first order differential value obtained from the displacement. Good.

[Embodiment 3]
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 3 is a configuration diagram showing the configuration of the stick-slip detection device according to the third embodiment of the present invention. This stick-slip detection device stops the operation of the diagnostic unit 300 based on the amount of change in the measured value of the displacement amount of the movable unit and the diagnostic unit 300 that determines the abnormality of the movable unit having the contact sliding unit. A diagnostic operation control unit 307 that performs the above control.

  The diagnosis unit 300 includes a displacement detection unit 301, a first state quantity calculation unit 302 (first calculation unit), a second state quantity calculation unit 303 (second calculation unit), a characteristic storage unit 304, and a second state quantity estimation. Unit 305 and diagnostic operation unit 306. The diagnostic operation control unit 307 includes a change amount calculation unit 371 and an operation control unit 372.

  The displacement detector 301 detects (measures) the displacement of a movable part such as a valve body and outputs a digital displacement signal. The displacement detector 301 outputs the detected displacement signal to the first state quantity calculator 302 and the second state quantity calculator 303 after the set delay time. On the other hand, the displacement detection unit 301 immediately outputs the detected displacement signal to the change amount calculation unit 371.

  The first state quantity calculation unit 302 calculates the mean square of the first-order difference values as the first state quantity from the displacement signal output from the displacement detection unit 301 as the measured value indicating the detected displacement of the movable part. In addition, the second state quantity calculation unit 303 calculates the mean square of the second-order difference value as the second state quantity from the displacement signal output from the displacement detection unit 301.

  The characteristic storage unit 304 stores the relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part that is obtained in advance during normal operation. For example, the characteristic storage unit 304 stores a relationship (characteristic expression) between the mean square of the first-order difference value and the mean square of the second-order difference value of the displacement signal in a state where the sliding of the movable part is normal. .

  The second state quantity estimation unit 305 uses the relationship stored in the characteristic storage unit 304 to calculate the second state quantity from the first state quantity calculated by the first state quantity calculation unit 302 (the root mean square of the first-order difference values). Is estimated to calculate the estimated state quantity.

  The diagnosis calculation unit 306 determines the abnormality of the movable part by comparing the second state quantity calculated by the second state quantity calculation unit 303 with the estimated state quantity. For example, the diagnosis calculation unit 306 calculates a difference between the mean square of the second-order difference value calculated by the second state quantity calculation unit 303 and the estimated state quantity estimated by the second state quantity estimation unit 305, for example, When the difference is larger than a predetermined value, it is determined that stick-slip has occurred.

  As described above, while the diagnosis unit 300 determines stick-slip (abnormality of the movable unit), in this embodiment, the diagnostic operation control unit 307 detects (measures) the movable unit detected by the displacement detection unit 301. By stopping the operation of the diagnosis calculation unit 306 based on the change amount of the displacement amount, the determination operation of the diagnosis unit 300 is stopped.

  In the diagnostic operation control unit 307, first, the change amount calculation unit 371 calculates the change amount from the displacement amount (displacement signal) of the movable part detected by the displacement detection unit 301. Next, the operation control unit 372 compares the set reference value with the calculated change amount, and if the change width of the calculated change amount in unit time exceeds the reference value, the diagnosis control unit 306 Stop operation. For example, when the operation control unit 372 outputs a stop signal, the operation of the diagnosis calculation unit 306 is stopped.

  Here, as described above, the displacement detection unit 301 outputs a displacement signal to the first state quantity calculation unit 302 and the second state quantity calculation unit 303 after the set delay time. Accordingly, after the operation control unit 372 outputs the comparison result between the reference value and the calculated change amount, the first control unit 302 and the second state calculation unit 303 can output a displacement signal. it can. As a result, the diagnosis operation control unit 307 can stop the operation before the diagnosis unit 300 (diagnosis calculation unit 306) performs the determination operation.

  In the present embodiment, the displacement detection unit 301 delays when the displacement is output to the first state quantity calculation unit 302 and the second state quantity calculation unit 303, so that the diagnosis operation control unit 307 causes the diagnosis unit 300 to Although the determination operation is controlled, the part where the delay is inserted is not limited to this part. Each state quantity calculation unit may delay the output of the state quantity to the diagnosis calculation unit 306, and the same can be done by delaying the diagnosis calculation unit 306 from outputting the diagnosis result.

  As described above, in the diagnosis unit 300, determination of stick-slip is stopped, and erroneous detection of stick-slip caused by the control state of the movable unit can be suppressed.

[Embodiment 4]
Next, Embodiment 4 of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram showing the configuration of the stick-slip detection device according to the fourth embodiment of the present invention. The stick-slip detection device includes a diagnosis unit 400 that determines abnormality of a movable part having a contact sliding part such as a control valve. In addition, the stick-slip detection device stops the operation of the diagnosis unit 400 based on the amount of change in the measured value of either the amount of displacement of the movable part such as the valve body or the process variable that changes due to the displacement of the movable part. A diagnostic operation control unit 407 that performs the above control.

  The diagnosis unit 400 includes a displacement detection unit 401, a first state quantity calculation unit 402 (first calculation unit), a second state quantity calculation unit 403 (second calculation unit), a characteristic storage unit 404, and a diagnosis calculation unit 406. Is provided.

  The displacement detector 401 detects (measures) the displacement of a movable part such as a valve body. The first state quantity calculation unit 402 calculates a first state quantity from the detected displacement. The second state quantity calculation unit 403 calculates a second state quantity from the detected displacement. The characteristic storage unit 404 stores the relationship between the first state quantity and the second state quantity obtained in advance from the displacement of the movable part during normal operation. The diagnosis calculation unit 406 is stored in the characteristic storage unit 404 and the relationship between the first state quantity calculated by the first state quantity calculation unit 402 and the second state quantity calculated by the second state quantity calculation unit 403. The abnormality of the movable part is determined by comparing the relationship.

  Next, the diagnostic operation control unit 407 will be described in more detail. For example, the regulating valve is automatically controlled from the outside from the outside, and is independently controlled by an adjusting mechanism of the valve itself. As a result of these controls, the displacement of the valve shaft (movable part) changes. In addition, process variables such as the flow rate of fluid passing through the control valve change corresponding to the amount of displacement of the valve shaft. The diagnosis operation control unit 407 controls the operation of the diagnosis unit 400 based on the amount of change in the measurement result (measurement value) such as the valve shaft displacement and the process variable.

  For example, the diagnostic operation control unit 407 compares the measured change width of the valve shaft with a preset reference value, and the measured change width of the valve shaft displacement exceeds the reference value. In this case, the abnormality determination operation in the diagnosis unit 400 is stopped.

  When control is performed so that the displacement of the valve shaft is greatly changed in a short time, it may be determined in the same manner as when stick-slip has occurred even in normal operation. On the other hand, the diagnosis operation control unit 407 stops the operation of the diagnosis unit 400 when the unit time change width of the measured value of the valve shaft displacement that reflects the change in the control command value exceeds the reference value. Slip detection errors can be suppressed. These operations are the same as those in the first embodiment. In addition, since the displacement of the valve shaft, which is a movable part, is also reflected in changes in process variables such as flow rate, the same applies to measurement values of process variables such as flow rate.

  Also in the present embodiment described above, as in the first embodiment described above, the diagnostic operation control unit 407 measures either the displacement amount of the movable part such as the valve body or the process variable that changes due to the displacement of the movable part. Since the operation of the diagnostic unit 400 is controlled based on the amount of change in value, it is possible to more accurately determine the state of stick-slip according to the state of control, such as the prevention of false detection of stick-slip. become. Further, the countermeasure for the time delay required to compare the displacement of the valve shaft and the variation of the process variable with the reference value is the same as in the first embodiment.

[Embodiment 5]
Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram showing the configuration of the stick-slip detection device according to the fifth embodiment of the present invention. This stick-slip detection device includes a diagnostic unit 500 that determines an abnormality of a movable part having a contact sliding part, and an operation of the diagnostic part 500 based on a change amount of a measured value of a displacement amount of the movable part. A diagnostic operation control unit 507 that performs control is provided.

  The diagnosis unit 500 includes a displacement detection unit 501, a first state quantity calculation unit 502 (first calculation unit), a second state quantity calculation unit 503 (second calculation unit), a characteristic storage unit 504, and a diagnosis calculation unit 506. Prepare. Further, the diagnostic operation control unit 507 includes a change amount calculation unit 571 and an operation control unit 572.

  The displacement detector 501 detects (measures) the displacement of a movable part such as a valve body and outputs a digital displacement signal. The displacement detection unit 501 outputs the detected displacement signal to the first state quantity calculation unit 502 and the second state quantity calculation unit 503 after the set delay time. On the other hand, the displacement detector 501 immediately outputs the detected displacement signal to the change amount calculator 571.

  The first state quantity calculation unit 502 calculates the mean square of the first-order difference value as the first state quantity from the displacement signal output from the displacement detection unit 501 as the measured value indicating the detected displacement of the movable part. Further, the second state quantity calculation unit 503 calculates the mean square of the second-order difference value as the second state quantity from the displacement signal output from the displacement detection unit 501.

  The characteristic storage unit 504 stores the relationship between the first state quantity and the second state quantity obtained in advance from the displacement of the movable part during normal operation. The diagnosis calculation unit 506 obtains the relationship between the first state quantity calculated by the first state quantity calculation unit 502 and the second state quantity calculated by the second state quantity calculation unit 503, and the obtained relationship and the specific memory The occurrence of stick-slip is detected by comparing the relationship stored in the unit 504.

  As described above, while the diagnosis unit 500 determines stick-slip (abnormality of the movable unit), in this embodiment, the diagnostic operation control unit 507 detects (measures) the movable unit detected by the displacement detection unit 501. The determination operation of the diagnosis unit 500 is stopped by stopping the operations of the first state amount calculation unit 502 and the second state amount calculation unit 503 based on the change amount of the displacement amount.

  In the diagnostic operation control unit 507, first, the change amount calculation unit 571 calculates the change amount from the displacement amount (displacement signal) of the movable part detected by the displacement detection unit 501. Next, the operation control unit 572 compares the set reference value with the calculated change amount, and if the change width of the calculated change amount in unit time exceeds the reference value, the first state amount calculation is performed. The calculation operation in the unit 502 and the second state quantity calculation unit 503 is stopped.

  Here, as described above, the displacement detection unit 501 outputs a displacement signal to the first state quantity calculation unit 502 and the second state quantity calculation unit 503 after the set delay time. Therefore, after the operation control unit 572 outputs the comparison result between the reference value and the calculated change amount, the first control unit 502 and the second state amount calculation unit 503 can output a displacement signal. it can. As a result, the diagnosis operation control unit 507 can stop the operation before the diagnosis unit 500 (diagnosis calculation unit 506) performs the determination operation.

  As described above, in the diagnosis unit 500, the determination of stick-slip is stopped, and the erroneous detection of stick-slip due to the control state of the movable unit as described above can be suppressed.

  By the way, in the above description, the displacement signal output from the displacement detection unit 501 is a digital signal, and the mean square of the first-order difference value is calculated as the first state quantity, and the second-order difference value is squared as the second state quantity. Although the average was calculated, it is not limited to this. As in equation (1), the absolute value average of the first-order difference values may be calculated as the first state quantity, and the square root of the root mean square of the first-order difference values may be calculated as the second state quantity. When the displacement signal is an analog signal, the mean square of the first order differential value may be calculated as the first state quantity, and the mean square of the second order differential value may be calculated as the second state quantity.

[Embodiment 6]
Next, Embodiment 6 of the present invention will be described with reference to FIG. FIG. 6 is a configuration diagram showing the configuration of the stick-slip detection device according to the sixth embodiment of the present invention. This stick-slip detection device includes a diagnosis unit 600 that determines abnormality of a movable part having a contact sliding part, and an operation of the diagnosis part 600 is stopped based on a change amount of a measured value of a displacement amount of the movable part. A diagnostic operation control unit 607 that performs control is provided.

  The diagnosis unit 600 includes a displacement detection unit 601, a first state quantity calculation unit 602 (first calculation unit), a second state quantity calculation unit 603 (second calculation unit), a characteristic storage unit 604, and a diagnosis calculation unit 606. Prepare. Further, the diagnostic operation control unit 607 includes a change amount calculation unit 671 and an operation control unit 672.

  The displacement detector 601 detects (measures) the displacement of a movable part such as a valve body and outputs a digital displacement signal. The displacement detection unit 601 outputs the detected displacement signal to the first state quantity calculation unit 602 and the second state quantity calculation unit 603 after the set delay time. On the other hand, the displacement detection unit 601 immediately outputs the detected displacement signal to the change amount calculation unit 671.

  The first state quantity calculation unit 602 calculates the mean square of the first-order difference value as the first state quantity from the displacement signal output from the displacement detection unit 601 as a measurement value indicating the detected displacement of the movable part. Further, the second state quantity calculation unit 603 calculates the mean square of the second-order difference value as the second state quantity from the displacement signal output from the displacement detection unit 601.

  The characteristic storage unit 604 stores the relationship between the first state quantity and the second state quantity obtained from the displacement of the movable part that is obtained in advance during normal operation. The diagnosis calculation unit 606 obtains the relationship between the first state quantity calculated by the first state quantity calculation unit 602 and the second state quantity calculated by the second state quantity calculation unit 603, and the obtained relationship and the specific memory The occurrence of stick-slip is detected by comparing the relationship stored in the unit 604.

  As described above, while the diagnosis unit 600 determines stick-slip (abnormality of the movable part), in this embodiment, the diagnosis operation control unit 607 detects the displacement of the movable part detected by the displacement detection unit 601. The determination operation of the diagnosis unit 600 is stopped by stopping the operation of the diagnosis calculation unit 606 based on the change amount of the amount.

  In the diagnostic operation control unit 607, first, the change amount calculation unit 671 calculates the change amount from the displacement amount (displacement signal) of the movable part detected by the displacement detection unit 601. Next, the operation control unit 672 compares the set reference value with the calculated change amount. When the change width of the calculated change amount in unit time exceeds the reference value, the diagnosis calculation unit 606 Stop operation.

Here, as described above, the displacement detection unit 601 outputs a displacement signal to the first state quantity calculation unit 602 and the second state quantity calculation unit 603 after the set delay time. Therefore, after the operation control unit 672 outputs the comparison result between the reference value and the calculated change amount, the first control unit 602 and the second state amount calculation unit 603 can output a displacement signal. it can. As a result, the diagnosis operation control unit 607 can stop the operation before the diagnosis unit 600 (diagnosis calculation unit 606) performs the determination operation.
Even in the case of the present embodiment, the location to be delayed is not limited to the output of the displacement detector 601. Similarly to the third embodiment described above, each state quantity calculation unit may delay the output of the state quantity to the diagnosis calculation unit 606, and the diagnosis calculation unit 606 may delay outputting the diagnosis result. Even so, it is the same.

  As described above, in the diagnosis unit 600, the determination of stick-slip is stopped, and the erroneous detection of stick-slip due to the control state of the movable unit as described above can be suppressed.

[Embodiment 7]
Next, Embodiment 7 of the present invention will be described with reference to FIG. FIG. 7 is a configuration diagram showing the configuration of the stick-slip detection device according to the seventh embodiment of the present invention. The stick-slip detection device is configured to operate the diagnosis unit 200 based on the diagnosis unit 200 that determines abnormality of the movable unit having the contact sliding unit and the measurement value change of the process variable that changes due to the displacement of the movable unit. A diagnostic operation control unit 707 that performs control such as stopping the control.

  The diagnosis unit 200 includes a displacement detection unit 201, a first state quantity calculation unit 202 (first calculation unit), a second state quantity calculation unit 203 (second calculation unit), a characteristic storage unit 204, and a second state quantity estimation. Unit 205 and diagnostic operation unit 206. About these structures, it is the same as that of Embodiment 2 mentioned above.

  In the present embodiment, the diagnostic operation control unit 707 includes a process variable measurement value reception unit 771, a change amount calculation unit 772, and an operation control unit 773.

  The process variable measurement value receiving unit 771 receives a measurement result of a process variable controlled by, for example, a control valve to be diagnosed by the diagnosis unit 200. Hereinafter, the case where the process variable is the flow rate of the fluid will be described. The change amount calculation unit 772 calculates a change amount per unit time set in advance from the change in the flow rate measurement value received by the process variable measurement value reception unit 771. The operation control unit 773 stops the operations of the first state amount calculation unit 202 and the second state amount calculation unit 203 when the change amount calculated by the change amount calculation unit 772 exceeds the set reference value. As a result, the determination operation of the diagnosis unit 200 is stopped.

  For example, it is assumed that control is performed such that the opening degree of the control valve is changed from 0% to 100% at a certain time t1. As a result of this control, the opening of the control valve changes from 0% to 100%. As a result, the flow rate of the fluid to be controlled in the flow path downstream from the control valve increases corresponding to the opening of the control valve, but until the effect of changing the opening of the control valve appears in the measured value of the flow meter Since there is usually a time delay, the increase in flow rate will start with a slight delay. This time is assumed to be t2. If the opening degree of the control valve changes abruptly in this way, as described above, erroneous detection of stick-slip in the diagnosis unit 200 is caused.

  Here, in the present embodiment, first, the process variable measurement value receiving unit 771 receives a flow rate measurement value that increases from time t2. The change amount calculation unit 772 calculates a first-order difference value for each unit time from the received flow rate measurement value. The flow rate measurement value changes in time series corresponding to the change in control, and the calculated first-order difference value becomes a large value at time t2. When this value exceeds the reference value, the operation control unit 773 outputs an operation stop signal that continues for a predetermined time from the time t2 to the first state quantity calculation unit 202 and the second state quantity calculation unit 203.

  On the other hand, the displacement detection unit 201 outputs the detected displacement signal to the first state quantity calculation unit 202 and the second state quantity calculation unit 203 after the set delay time. For this reason, until the above-described operation stop signal is output, the displacement signal input to the first state quantity calculation unit 202 and the second state quantity calculation unit 203 changes in the sudden displacement that is the cause of the operation stop signal. Never appears.

  Further, when the above-described operation stop signal is received by the first state quantity calculation unit 202 and the second state quantity calculation unit 203, the first state quantity calculation unit 202 and the second state quantity calculation unit 203 stop the calculation operation. . The first state quantity calculation unit 202 and the second state quantity calculation unit 203 stop the calculation operation while receiving the operation stop signal.

  As a result, when the displacement signal detected at time t1 is delayed and output from the displacement detection unit 201, the first state quantity calculation unit 202 and the second state quantity calculation unit 203 perform the calculation operation by the operation stop signal. This means that the calculation of the state quantity has stopped. In other words, a large value of the first-order difference value of the displacement signal determined to be stick-slip is excluded from the calculation operation. Therefore, for a predetermined time during which the operation stop signal is output by the operation control unit 773, the diagnosis unit 200 stops the determination of stick-slip, and erroneous stick-slip detection can be suppressed.

  In addition, since the detection error is suppressed based on the amount of change in the measured value of the process variable that changes due to the displacement of the movable part, a single diagnosis operation control unit can be used to set a plurality of diagnosis targets and diagnosis units. On the other hand, it is possible to control the diagnostic operation. For example, if the result of fluid control by multiple control valves affects one flow meter, multiple adjustments are made based on the amount of change in the measured value of the flow rate (process variable) measured by this flow meter. It is possible to control stick-slip detection (diagnosis operation) in the valve. In this way, the number of devices can be reduced, and the cost required for diagnosis can be reduced. When the operation of a plurality of diagnosis units is controlled by one diagnosis operation control unit, it is preferable to determine the reference value for each object (for example, a control valve) diagnosed by each diagnosis unit, but the object having the smallest reference value It is also possible to make it common according to.

[Embodiment 8]
Next, an eighth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a configuration diagram showing the configuration of the stick-slip detection device according to the eighth embodiment of the present invention. This stick-slip detection device includes a diagnostic unit 200 that determines an abnormality of a movable unit having a contact sliding unit. Diagnosis section 200 is the same as in the second and seventh embodiments.

  Further, the stick-slip detection device according to the eighth embodiment sends a determination signal for stopping the operation of the diagnosis unit 200 based on the change amount of the measured value of the process variable (flow rate) that changes due to the displacement of the movable part. And an operation control unit 876 for stopping the operation of the diagnosis unit 200 based on the determination signal sent from the diagnosis operation control external system 807. The flow rate is measured by a flow meter 809 having a movable part, for example, disposed downstream of the control valve, and the flow rate value measured by the flow meter 809 is notified (transmitted) to the diagnostic operation control external system 807. The determination signal sent from the diagnostic operation control external system 807 is received by the receiving unit 875 connected via the network 808 and sent to the operation control unit 876.

  In the present embodiment, the diagnostic operation control external system 807 includes a flow rate measurement value reception unit 871, a change amount calculation unit 872, a change amount determination unit 873, and a transmission unit 874. The diagnostic operation control external system 807 is preferably in the same system as the external control system that determines the control state of the movable part, but may be realized as a separate system.

  The flow rate measurement value receiving unit 871 receives from the flow meter 809 a flow rate measurement value of a fluid to be diagnosed by the diagnosis unit 200, for example, controlled by a control valve. When the diagnostic operation control external system 807 is incorporated in the device of the flow meter 809, acquisition of the flow rate measurement value can be realized as delivery of data in the device. When implemented as a separate system, it is necessary to be able to receive flow rate measurements in real time by communicating with the flow meter 809. The change amount calculation unit 872 calculates a change amount per unit time that is set in advance based on the received change in the flow rate measurement value. The change amount determination unit 873 outputs an operation stop signal when the change amount calculated by the change amount calculation unit 872 exceeds a set reference value. The transmission unit 874 transmits the operation stop signal output from the change amount determination unit 873 to the reception unit 875 via the network 808.

  On the other hand, the displacement detection unit 201 outputs the detected displacement signal to the first state quantity calculation unit 202 and the second state quantity calculation unit 203 after the set delay time. For this reason, until the above-described operation stop signal is output, the displacement signal input to the first state quantity calculation unit 202 and the second state quantity calculation unit 203 changes in the sudden displacement that is the cause of the operation stop signal. Never appears.

  In addition, when the above-described operation stop signal is received by the reception unit 875, the operation control unit 876 stops the calculation operations of the first state quantity calculation unit 202 and the second state quantity calculation unit 203. While the reception unit 875 receives the operation stop signal, the operation control unit 876 stops the calculation operations of the first state quantity calculation unit 202 and the second state quantity calculation unit 203.

  As a result, when the displacement signal that has already been detected is delayed and output from the displacement detector 201, the first state quantity calculator 202 and the second state quantity calculator 203 stop the calculation operation by the operation stop signal. The calculation of the state quantity has stopped. In other words, a large value of the first-order difference value of the displacement signal determined to be stick-slip is excluded from the calculation operation. Therefore, for a predetermined time during which the operation stop signal is transmitted from the transmission unit 874, the determination of stick-slip is stopped in the diagnosis unit 200, and erroneous detection of stick-slip can be suppressed.

  As described above, in the diagnosis unit 200, the determination of stick-slip is stopped similarly to the above-described seventh embodiment, and the erroneous detection of stick-slip caused by the control state of the movable unit as described above can be suppressed. Become.

[Embodiment 9]
Next, Embodiment 9 of the present invention will be described with reference to FIG. FIG. 9 is a configuration diagram showing the configuration of the stick-slip detection device in the embodiment of the present invention. The stick-slip detection device includes a diagnosis unit 100 that determines abnormality of a movable part having a contact sliding part such as a control valve.

  In addition, the stick-slip detection device is a diagnostic operation control unit 907 that determines whether the diagnosis unit 100 is correct based on the amount of change in the measurement value of the flow rate that changes in accordance with the displacement of the valve body that is the movable unit. Is provided. The flow rate is measured by a flow meter 910 having a movable part, for example, arranged downstream of the control valve, and the flow rate value measured by the flow meter 910 is notified to the diagnostic operation control unit 907.

  The diagnosis unit 100 includes a displacement detection unit 101, a first state quantity calculation unit (first calculation unit) 102, a second state quantity calculation unit (second calculation unit) 103, a characteristic storage unit 104, and a second state quantity estimation. Unit 105 and diagnostic operation unit 106. Diagnosis unit 100 is the same as that in the first embodiment.

  The displacement detection unit 101 detects (measures) the displacement of a movable part such as a valve body. The first state quantity calculator 102 calculates the first state quantity from the detected displacement of the movable part. The second state quantity calculation unit 103 calculates a second state quantity from the detected displacement of the movable part. The characteristic storage unit 104 stores the relationship between the first state quantity and the second state quantity obtained in advance from the displacement of the movable part during normal operation.

  The second state quantity estimation unit 105 uses the relationship stored in the characteristic storage unit 104 to estimate the second state quantity from the first state quantity calculated by the first state quantity calculation unit 102 and estimate the state Calculate the amount. The diagnosis calculation unit 106 compares the second state quantity calculated by the second state quantity calculation unit 103 with the estimated state quantity to determine an abnormality of the movable part, and an abnormality is detected (abnormality detection signal). Is output.

  Next, the diagnostic operation control unit 907 will be described. The diagnostic operation control unit 907 includes a flow rate measurement value reception unit 971, a measurement value storage unit 972, a change amount calculation unit 973, a change amount determination unit 974, a change amount calculation control unit 975, and a diagnosis result determination unit 976.

  The flow rate measurement value receiving unit 971 receives the flow rate measurement value of the fluid controlled by the control valve from the flow meter 910. The flow rate measurement value receiving unit 971 receives the flow rate measurement values from the flow meter 910 in time series. The measurement value storage unit 972 stores the received flow rate measurement values in time series. The change amount calculation unit 973 calculates a change amount per unit time that is set in advance from a change in the flow rate measurement value stored in the measurement value storage unit 972 in time series. In addition, when the change amount calculation unit 973 receives a start instruction signal from the change amount calculation control unit 975, the change amount calculation unit 973 starts the above-described calculation operation. The change amount determination unit 974 outputs an operation stop signal when the change amount calculated by the change amount calculation unit 973 exceeds the set reference value.

  The change amount calculation control unit 975 receives the abnormality detection signal output from the diagnosis calculation unit 106, notifies the change amount calculation unit 973 of a start instruction signal, and starts the change amount calculation operation. Further, the diagnosis result determination unit 976 determines whether the abnormality detection signal output and received from the diagnosis calculation unit 106 is correct based on the presence / absence of the operation stop signal output from the change amount determination unit 974, and detects an abnormality ( Notify the occurrence of (stick slip). When the diagnosis result determination unit 976 receives the operation stop signal in addition to the abnormality signal, the diagnosis result determination unit 976 determines that the received abnormality signal is an erroneous determination and does not notify the occurrence of the abnormality.

  The above-described embodiment is characterized in that the diagnostic operation control unit 907 does not control the operation of each unit of the diagnostic unit 100 but determines whether the abnormality is determined by the diagnostic unit 100 (diagnosis calculation unit 106). There is. According to the present embodiment thus configured, the diagnostic operation control unit 907 may be added to the environment where the diagnostic unit 100 is already installed without changing the diagnostic unit 100. Changes can be suppressed.

  Here, the state of displacement of the movable part at the time of measurement of the displacement measurement value (displacement detection result) by the displacement detection part 101, which is a basis for determining whether the diagnosis of the movable part is abnormal, is measured by the flow meter 910. There is a time delay before it is reflected in the measured flow rate. This is due to the transport delay required for fluid to flow from the control valve to the flow meter and the measurement delay of the flow meter itself. Also, it takes time to calculate the abnormality determination result based on the detected displacement. This is because the calculation of the state quantity, which is the basis for determining the abnormality, requires displacement data for a certain period of time as shown in the equations (1) to (4) and (7) to (8). is there. Further, in most cases, the delay time in the flow rate measurement and the determination result calculation time are different.

  For this reason, after the abnormality detection signal output from the diagnosis calculation unit 106 is received by the change amount calculation control unit 975, the flow rate measurement value used for the change amount calculation by the change amount calculation unit 973 is the value of the measurement time to be calculated. It is necessary to set the range in consideration of the calculation time of the determination result by the diagnosis calculation unit 106 and the delay time of the flow rate measurement.

  Here, it is assumed that the determination result of the diagnostic calculation unit 106 is based on the displacement measured by the displacement detection unit 101 between the times t1 and t2. Also, let Tf be the time (delay) required until the displacement state of the movable part is reflected in the flow rate measurement value. In this case, the change amount calculation by the change amount calculation unit 973 may be performed using flow rate measurement values from time t1 + Tf to t2 + Tf.

  For example, when the calculation time of the determination result is longer than the flow measurement delay time, the time t1 + Tf has already passed when the change amount calculation unit 973 receives the start instruction signal from the change amount calculation control unit 975. Later. Therefore, in order to calculate the amount of change, the flow rate measurement value received by the flow rate measurement value receiving unit 971 from the time t1 + Tf to the present and stored in the measurement value storage unit 972 is required.

  Further, for example, when the delay time of the flow rate measurement is longer than the calculation time of the determination result, when the change amount calculation unit 973 receives the start instruction signal from the change amount calculation control unit 975, the time t1 + Tf is still is not. Therefore, after the time t1 + Tf is reached, the amount of change may be calculated using the flow rate measurement value received by the flow rate measurement value receiving unit 971. In this case, the measurement value storage unit 972 may not be provided.

  In any case, the time for measuring the displacement of the movable part used for calculation of the determination result can be grasped from the specification of the diagnosis part, and the delay time of the flow rate measurement is a measurable time. Therefore, it is possible to set the time range described above.

  The present invention is not limited to the embodiments described above, and many of them, including combinations of the embodiments, can be made by those having ordinary knowledge in the art within the technical idea of the present invention. It is obvious that a variation of can be implemented.

  For example, in Embodiment 9 described above, when the diagnostic operation control unit receives an abnormal signal from the diagnostic calculation unit, the correctness / incorrectness of the determination of the abnormality is determined. However, the present invention is not limited to this. For example, the amount of change is always calculated, and while the calculated amount of change exceeds a set reference value, a signal indicating that the state is not suitable for determination of abnormality may be continuously output. Good. If an abnormality is determined by the diagnostic calculation unit while this signal is being output, it can be determined that the determination of the abnormality is an erroneous determination.

  DESCRIPTION OF SYMBOLS 100 ... Diagnosis part, 101 ... Displacement detection part, 102 ... 1st state quantity calculation part (1st calculation means), 103 ... 2nd state quantity calculation part (2nd calculation means), 104 ... Characteristic storage part, 105 ... 2nd state quantity estimation part, 106 ... Diagnosis calculation part, 107 ... Diagnosis operation control part.

Claims (14)

A displacement detecting means for detecting the displacement of the movable part having the contact sliding part;
First calculating means for calculating a first state quantity from the displacement;
Second computing means for computing a second state quantity from the displacement;
A characteristic storage unit that stores a relationship between a first state quantity and a second state quantity obtained from a displacement of the movable part that is obtained in advance during normal operation;
State quantity estimating means for calculating the estimated state quantity by estimating the second state quantity from the first state quantity calculated by the first computing means using the relationship stored in the characteristic storage unit; ,
A diagnostic unit for determining an abnormality of the movable part, comprising: a diagnostic calculation unit for determining an abnormality of the movable part by comparing the second state quantity calculated by the second calculation means and the estimated state quantity; ,
A diagnostic operation control unit configured to control an operation of the diagnostic unit based on a change amount of a measured value of any one of a displacement amount of the movable unit and a process variable that varies depending on the displacement of the movable unit. Stick-slip detector. A displacement detecting means for detecting the displacement of the movable part having the contact sliding part;
First calculating means for calculating a first state quantity from the displacement;
Second computing means for computing a second state quantity from the displacement;
A characteristic storage unit that stores a relationship between a first state quantity and a second state quantity obtained from a displacement of the movable part that is obtained in advance during normal operation;
By comparing the relationship between the first state quantity calculated by the first calculation means and the second state quantity calculated by the second calculation means with the relation stored in the characteristic storage unit. A diagnostic unit for determining abnormality of the movable part, comprising: a diagnostic calculation means for determining abnormality of the movable part;
A diagnostic operation control unit configured to control an operation of the diagnostic unit based on a change amount of a measured value of any one of a displacement amount of the movable unit and a process variable that varies depending on the displacement of the movable unit. Stick-slip detector. The stick-slip detection device according to claim 1 or 2,
The diagnostic operation controller is
A change amount calculating means for calculating a change amount of the displacement of the movable part detected by the displacement detecting means;
An operation control means for detecting that the change amount calculated by the change amount calculation means exceeds a preset threshold value and controlling the operation of the diagnosis section, . The stick-slip detection device according to claim 1 or 2,
The diagnostic operation controller is
A change amount calculating means for calculating a change amount of the measured value of the process variable;
An operation control means for detecting that the change amount calculated by the change amount calculation means exceeds a preset threshold value, and stopping the operation of the diagnosis unit. . In the stick slip detection device according to any one of claims 1 to 4,
The diagnostic operation control unit controls the operation of the diagnostic unit by stopping the operations of the first calculation unit and the second calculation unit. In the stick slip detection device according to any one of claims 1 to 4,
The diagnostic operation control unit controls the operation of the diagnostic unit by stopping the operation of the diagnostic calculation means. In the stick slip detection device according to any one of claims 1 to 6,
The diagnostic operation controller is
Based on the abnormality determination by the diagnostic calculation means, start the operation control of the diagnostic unit,
Stick stick slip characterized by determining whether or not an abnormality is judged by the diagnostic calculation means based on a change amount of a measured value of any one of a displacement amount of the movable portion and a process variable that is changed by the displacement of the movable portion. Detection device. A displacement detecting means for detecting the displacement of the movable part having the contact sliding part;
First calculating means for calculating a first state quantity from the displacement;
Second computing means for computing a second state quantity from the displacement;
A characteristic storage unit that stores a relationship between a first state quantity and a second state quantity obtained from a displacement of the movable part that is obtained in advance during normal operation;
State quantity estimating means for calculating the estimated state quantity by estimating the second state quantity from the first state quantity calculated by the first computing means using the relationship stored in the characteristic storage unit; ,
A diagnostic unit for determining an abnormality of the movable part, comprising: a diagnostic calculation unit for determining an abnormality of the movable part by comparing the second state quantity calculated by the second calculation means and the estimated state quantity; ,
A diagnostic operation control unit that determines whether or not the abnormality is determined by the diagnostic calculation unit based on a change amount of a measured value of any one of a displacement amount of the movable portion and a process variable that changes due to the displacement of the movable portion. A stick-slip detector characterized by that. Detecting the displacement of the movable part with the contact sliding part,
A first state quantity is calculated from the displacement,
A second state quantity is calculated from the displacement,
Using the relationship between the first state quantity and the second state quantity obtained from the displacement during normal operation of the movable part obtained in advance, the second state quantity is calculated from the calculated first state quantity. To calculate the estimated state quantity,
Determining the abnormality of the movable part by comparing the calculated second state quantity and the estimated state quantity;
The stick-slip detection method characterized in that the abnormality determination operation is controlled based on a change amount of a measured value of any one of a displacement amount of the movable portion and a process variable that changes due to the displacement of the movable portion. Detecting the displacement of the movable part with the contact sliding part,
A first state quantity is calculated from the displacement,
A second state quantity is calculated from the displacement,
The relationship between the first state quantity and the second state quantity obtained from the displacement during normal operation of the movable part determined in advance, and between the calculated first state quantity and the second state quantity. By comparing the relationship and determining the abnormality of the movable part,
The stick-slip detection method characterized in that the abnormality determination operation is controlled based on a change amount of a measured value of any one of a displacement amount of the movable portion and a process variable that changes due to the displacement of the movable portion. The stick-slip detection method according to claim 9 or 10,
Calculate the amount of change in the displacement of the movable part,
A stick-slip detection method, wherein the abnormality determination operation is stopped when the calculated change amount exceeds a preset threshold value. The stick-slip detection method according to claim 9 or 10,
Calculate the amount of change in the measured value of the process variable,
A stick-slip detection method, wherein the abnormality determination operation is stopped when the calculated change amount exceeds a preset threshold value. In the stick slip detection method according to any one of claims 9 to 12,
Stopping the determination operation of the abnormality by determining whether the abnormality is correct based on the amount of change in the measured value of any one of the displacement amount of the movable portion and the process variable that changes due to the displacement of the movable portion. A stick-slip detection method characterized by the above. Detecting the displacement of the movable part with the contact sliding part,
A first state quantity is calculated from the displacement,
A second state quantity is calculated from the displacement,
Using the relationship between the first state quantity and the second state quantity obtained from the displacement during normal operation of the movable part obtained in advance, the second state quantity is calculated from the calculated first state quantity. To calculate the estimated state quantity,
Determining the abnormality of the movable part by comparing the calculated second state quantity and the estimated state quantity;
A stick-slip detection method comprising: determining whether the abnormality is correct or not based on a change amount of a measured value of any one of a displacement amount of the movable portion and a process variable that changes due to the displacement of the movable portion.

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